Retainer ring structure for chemical-mechanical polishing machine and method for manufacturing the same

ABSTRACT

A retainer ring structure for a chemical-mechanical polishing (CMP) machine includes: an insert ring made of metal and having a plurality of holes formed at the top surface thereof and coupled to a head of the CMP machine; an insert pin made of resin, including a body having a hollow portion of which the top surface is opened and one or more elongated grooves formed at side surfaces thereof in a longitudinal direction, and press-fitted into a hole of the insert ring so as to be subjected to a tapping process; and an outer ring formed to surround the insert pin and the insert ring.

BACKGROUND OF THE INVENTION

The present invention relates to a retainer ring structure for a chemical-mechanical polishing (CMP) machine, and more particularly, to a retainer ring structure for a CMP machine and a method for manufacturing the same, which prevents external exposure of a metallic ring of a retainer ring structure to fix the position of a silicon wafer during a CMP process, thereby preventing contamination and corrosion of the metallic ring and improving durability, and uses a low-priced metallic material to reduce the manufacturing cost, thereby increasing marketability.

With the increase in operating speed and integration degree of semiconductor devices, the increase in number of interconnection layers and the miniaturization of interconnection patterns in a multilayer interconnection structure have been required more and more. The multilayer interconnection technology is an important issue for a sub-micron process.

In particular, as a process margin for focus depth of an exposure system for realizing micro patterns shrinks with the advent of sub-0.35 μm process, a global planarization technique for a chip area is required to secure a sufficient focus depth.

Thus, a system referred to as chemical-mechanical polishing (CMP) machine is widely used to realize the global planarization technique. The CMP machine is essentially applied to a semiconductor device fabrication process, and research is being actively conducted on next-generation devices. The CMP machine is mainly applied to logic devices requiring multilayer interconnections to increase the operating speed of devices. However, as more and more memory devices employ a multilayer structure, application of the CMP machine to the memory devices is gradually increasing.

The CMP machine includes a retainer ring installed on a polishing head to fix a wafer, in order to perform a mechanical operation. The retainer ring is used to fix the position of a held wafer.

Since the retainer ring is made of resin such as plastic, the retainer ring has a low strength. Furthermore, a lot of time is required for a planarization process of the ring before the CMP process, and partial abrasion may occur due to the imbalance of force when a cover bolt is tightened.

Therefore, rings made of metal and resin such as plastic may be used. In this case, however, there are difficulties in coupling the metallic ring and the resin ring, and thus workability inevitably decreases. During the coupling operation, boding or welding may be used, but partial abrasion may occur due to the incomplete function and non-uniform coupling.

Furthermore, as bolt holes formed in the metallic ring are exposed to the outside, contamination may occur due to a polishing agent, and corrosion may easily occur to reduce the durability.

SUMMARY OF THE INVENTION

An embodiment of the present invention is directed to a retainer ring structure for a CMP machine and a method for manufacturing the same, which prevents external exposure of a metallic ring of a retainer ring structure, thereby preventing contamination and corrosion of the metallic ring and improving durability, and uses a low-priced metallic material to reduce the manufacturing cost, thereby increasing marketability.

According to an embodiment of the present invention, a retainer ring structure for a CMP machine includes: an insert ring made of metal and having a plurality of holes formed at the top surface thereof and coupled to a head of the CMP machine; an insert pin made of resin, including a body having a hollow portion of which the top surface is opened and one or more elongated grooves formed at side surfaces thereof in a longitudinal direction, and press-fitted into a hole of the insert ring so as to be subjected to a tapping process; and an outer ring formed to surround the insert pin and the insert ring.

According to another embodiment of the present invention, a retainer ring structure for a CMP machine includes: an insert ring made of metal and having a plurality of holes formed at the top surface thereof and coupled to a head of the CMP machine and a female screw thread formed therein; an insert pin made of resin and including a cylindrical body having a hollow portion of which the top surface is opened and a male screw thread formed at side surfaces thereof, wherein the inserting is screwed to a hole of the insert ring so as to be subjected to a tapping process; and an outer ring formed to surround the insert pin and the insert ring.

According to another embodiment of the present invention, a method for manufacturing a retainer ring structure for a CMP machine includes: forming a plurality of holes at the top surface of an insert ring made of metal such that a head of the CMP machine is coupled to the holes; coupling a plurality of insert pins made of resin to the plurality of holes of the insert ring, the insert pins each including a body having a hollow portion of which the top surface is opened and one or more elongated grooves formed at side surfaces of the body in a longitudinal direction; mounting the insert ring having the insert pins coupled thereto in a mold, and injection-molding resin to form an outer ring surrounding the insert ring; and tapping the insert pins.

According to another embodiment of the present invention, a method for manufacturing a retainer ring structure for a CMP machine includes: forming a plurality of holes at the top surface of an insert ring made of metal such that a head of the CMP machine is coupled to the holes, and forming a female screw thread inside the insert ring; coupling a plurality of insert pins made of resin to the plurality of holes of the insert ring, the insert pins each including a cylindrical body having a hollow portion of which the top surface is opened and a male screw formed at side surfaces of the body; mounting the insert ring having the insert pins coupled thereto in a mold, and injection-molding resin to form an outer ring surrounding the insert ring; and tapping the insert pins.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a CMP machine according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of an insert ring of a retainer ring structure according to an embodiment of the present invention.

FIG. 3 is a schematic perspective view of an insert ring of a retainer pin structure according to the embodiment of the present invention.

FIG. 4 illustrates that insert pin according to the embodiment of the present invention is press-fitted into the insert ring.

FIG. 5 is a schematic perspective view of the retainer ring structure according to the embodiment of the present invention.

FIG. 6 illustrates that an insert pin according to another embodiment of the present invention is press-fitted into an insert ring.

FIG. 7 is a flowchart for explaining a method for manufacturing the retainer ring structure according to the embodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be constructed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present invention.

Referring to FIG. 1, a retainer ring structure 10 according to an embodiment of the present invention will be described as follows.

A CMP machine includes a main body 108 and a polishing head 112. The main body 108 includes a polishing platen 110 mounted on the top surface thereof and a polishing pad 106 installed on the top surface of the polishing platen 110.

The polishing head 112 includes a retainer ring structure 10 to fix a wafer 100, a polishing housing 102 having the structure 10 mounted thereon, and a rotating arm 104. The polishing housing 102 is rotated by the rotating arm 104.

The polishing platen 110 includes a polishing pad 106 provided on the top surface thereof, and the polishing pad 106 serves to polish the surface of the wafer 100 in a state where the polishing pad 106 is contacted with the surface of the wafer 100. Furthermore, the polishing platen 110 has a rotation driving shaft 114 formed at the bottom thereof and connected to a driving unit, and performs an orbital motion through the driving unit.

Referring to FIGS. 2 to 5, the retainer ring structure 10 includes an insert ring 14, a plurality of insert pins 16, and an outer ring 12. The insert ring 14 is made of metal and has a plurality of holes 15 formed at the top surface thereof and coupled to the head 112 of the CMP machine. The plurality of insert pins 16 are made of resin and press-fitted in the holes 15 of the insert ring so as to be subject to a tapping process. The outer ring 12 is formed to surround the insert pins 16 and the insert ring 14.

Referring to FIG. 3, the insert pin 16 includes a body 17 and two elongated grooves 18. The body 17 has a hollow portion of which the top surface is opened, and the grooves 18 are formed at side surfaces of the body 17 in a longitudinal direction of the insert pin 16.

The reason to provide the grooves 18 is in order to facilitate the tapping process for the insert pin 16 because resin used as an injection-molded material in an injection molding process to be described below is introduced into the grooves 18 and thus the insert pin 16 is integrated with the outer ring 12 to be formed afterwards.

Thus, it is obvious to those skilled in the art that the shape and number of grooves 18 are not limited.

The insert ring 14 having the plurality of holes coupled to the head of the CMP machine has a female screw thread formed therein, and the insert pin 16 has a male screw thread formed therein. Thus, the insert ring 14 and the insert pin 16 may be screwed to each other.

Referring to FIG. 6, a protrusion 30 may be formed at a front end of the insert pin 16 and fixed to a predetermined portion of an injection mold. The protrusion 30 formed at the front end of the insert pin 16 may be cut after an injection molding process, and then subjected to the tapping process.

Thus, since the insert ring 14 is surrounded by the outer ring 12 and the bolt holes coupled to the head of the CMP machine are not exposed to the outside, the insert ring 14 may be made of a low-priced metallic material.

Referring to FIG. 7, a method for manufacturing the retainer ring structure according to the embodiment of the present invention will be described as follows.

First, a plurality of holes 15 to be coupled to the head of the CMP machine are formed at the top surface of an insert ring 14 made of metal at step S12, and a plurality of insert pins 16 made of resin are coupled to the plurality of holes 15 of the insert ring 14 at step S14.

Then, the insert ring 14 having the insert pins 16 coupled thereto is mounted in a mold, and resin is injection-molded to form an outer ring 12 surrounding the insert ring 14 at step S16.

Finally, as the insert pin 16 is subjected to a tapping process, the insert ring 14 has no surfaces exposed to the outside at step S18.

At this time, the insert pin 16 includes a body 17 having a hollow portion of which the top surface is opened and two elongated grooves 18 formed at side surfaces of the body 17 in the longitudinal direction thereof.

Furthermore, a female screw thread is formed inside a the insert ring 14 having the plurality of holes formed at the top surface thereof and coupled to the head of the CMP process, and a male screw thread is formed outside the insert pin 16. Thus, the insert ring 14 and the insert pin 16 may be screwed to each other.

In another embodiment, the insert pin 16 may be formed to have a protrusion 30 and, a body portion. The protrusion 30 is mounted in the mold during the injection molding process and then cut through a cutting process, and the body portion is connected to one end of the body 1 and subjected to a tapping process after the injection molding process.

According to the embodiments of the present invention, as the metallic ring surrounded by the resin ring is prevented from being exposed to the outside, the contamination and corrosion of the metallic ring may be prevented, and the durability may be improved. Furthermore, a low-priced metallic material may be used to reduce the manufacturing cost, which makes it possible to increase marketability.

While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. 

What is claimed is:
 1. A retainer ring structure for a chemical-mechanical polishing (CMP) machine, comprising: an insert ring made of metal and having a plurality of holes formed at the top surface thereof and coupled to a head of the CMP machine; an insert pin made of resin, comprising a body having a hollow portion of which the top surface is opened and one or more elongated grooves formed at side surfaces thereof in a longitudinal direction, and press-fitted into a hole of the insert ring so as to be subjected to a tapping process; and an outer ring formed to surround the insert pin and the insert ring.
 2. A retainer ring structure for a CMP machine, comprising: an insert ring made of metal and having a plurality of holes formed at the top surface thereof and coupled to a head of the CMP machine and a female screw thread formed therein; an insert pin made of resin and comprising a cylindrical body having a hollow portion of which the top surface is opened and a male screw thread formed at side surfaces thereof, wherein the inserting is screwed to a hole of the insert ring so as to be subjected to a tapping process; and an outer ring formed to surround the insert pin and the insert ring.
 3. A method for manufacturing a retainer ring structure for a CMP machine, comprising: forming a plurality of holes at the top surface of an insert ring made of metal such that a head of the CMP machine is coupled to the holes; coupling a plurality of insert pins made of resin to the plurality of holes of the insert ring, the insert pins each including a body having a hollow portion of which the top surface is opened and one or more elongated grooves formed at side surfaces of the body in a longitudinal direction; mounting the insert ring having the insert pins coupled thereto in a mold, and injection-molding resin to form an outer ring surrounding the insert ring; and tapping the insert pins.
 4. The method of claim 3, wherein each of the insert pins has a protrusion mounted in the mold and cut after injection molding and a body portion connected to one end of the body and subjected to a tapping process after injection molding.
 5. A method for manufacturing a retainer ring structure for a CMP machine, comprising: forming a plurality of holes at the top surface of an insert ring made of metal such that a head of the CMP machine is coupled to the holes, and forming a female screw thread inside the insert ring; coupling a plurality of insert pins made of resin to the plurality of holes of the insert ring, the insert pins each including a cylindrical body having a hollow portion of which the top surface is opened and a male screw formed at side surfaces of the body; mounting the insert ring having the insert pins coupled thereto in a mold, and injection-molding resin to form an outer ring surrounding the insert ring; and tapping the insert pins. 